White light emission from fluorescent ionic liquids in the solution and gel forms using RGB system

Abstract

A single blend of red, green, and blue (RGB) chromophores made of organic molecules is of greater significance in the evolution of inexpensive, metal-free, color-tunable white light emission (WLE). In this paper, three ionic liquid-based compounds viz. [TPA-SB][Br], [PTZ-SB][Br], and RhB-IL were designed for the effective generation of white light in the solution state with the Commission Internationale d’Eclairage (CIE) coordinates of (0.33, 0.33). The mechanism of WLE involves Förster resonance energy transfer (FRET) with simultaneous emissions, as confirmed by several mechanistic investigations, including PL titration, spectrum overlap, Forster distance calculations and fluorescence lifetime experiment. Moreover, this novel mixture was immobilized in gelatin gel to obtain WLE in gel phase with a CIE of (0.33, 0.31). Furthermore, the gel was applied as a coating on a UV LED to reveal its applicability as an affordable organic coating for WLE by simultaneous emission. Notably, this is the first report on the emanation of white light from simple ionic liquid system via Forster resonance energy transfer.